Grid Size

Lateral Finite Difference

Central Finite Difference

Mimetic Method

20

0.1985

0.0153

0.0037

30

0.1350

0.0069

0.0016

40

0.1022

0.0039

0.0009

50

0.0823

0.0025

0.0006

60

0.0688

0.0017

0.0004

70

0.0592

0.0013

0.0003

Convergence rate in space

0.9301

1.9486

2.0300

Convergence rate in time

0.4650

0.9743

1.0150